Touch location determination using bending mode sensors and multiple detection techniques

• US 7,683,890 B2
• Filed: 04/28/2005
• Issued: 03/23/2010
• Est. Priority Date: 04/28/2005
• Status: Expired due to Fees

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Geaghan, Bernard O.
• Primary Examiner(s): Nguyen; Kevin M
• Assistant Examiner(s): Lee, Jr.; Kenneth B
• Application Number:
  US11/116,463
• Publication Number:
  US 20060244732A1
• Time in Patent Office: 1,790 Days
• Field of Search: 345173-179, 178 1801- 1811, 178 1901- 1907
• US Class Current: 345/173
• CPC Class Codes: G06F 3/041 Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
• CPC Class Codes: G06F 3/04142 the force sensing means being located peripherally, e.g. disposed at the corners or at the side of a touch sensing plate
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/043 using propagating acoustic waves
• CPC Class Codes: G06F 3/0436 in which generating transducers and detecting transducers are attached to a single acoustic waves transmission substrate

Abstract

A touch sensing system and method uses bending mode sensors and a multiplicity of disparate touch location detection techniques to generate touch location information. A number of bending mode sensors are coupled to a touch sensitive surface. A number of disparate touch location detection techniques are provided, at least one of which uses signals generated by the bending mode sensors. Touch location information is developed using the disparate touch location detection techniques. The touch location information may include the location of a touch to the touch sensitive surface.

Claims

1. A touch sensing method, comprising:

providing a plurality of bending mode sensors coupled to a touch sensitive surface;

providing a plurality of disparate touch location detection techniques; and

developing touch location information using the disparate touch location detection techniques;

wherein the disparate touch location detection techniques comprise a first and second touch location detection technique, at least one of which uses signals generated by the bending mode sensors; and

wherein, for a given touch on the touch sensitive surface, the developing comprises determining a coarse location for the touch using the first touch location technique, and using the determined coarse location to enhance a touch location determination made by the second touch location technique to provide a fine location for the touch, the fine location being more accurate than the first and second touch location techniques alone.

2. The method of claim 1, wherein at least two of the plurality of disparate touch location detection techniques use signals generated by the bending mode sensors.

3. The method of claim 2, wherein the at least two of the plurality of disparate touch location detection techniques that use signals generated by the bending mode sensors differ in terms of frequency response.

4. The method of claim 1, wherein at least some of the plurality of disparate touch location detection techniques are capable of independently detecting a touch location.

5. The method of claim 1, wherein providing the plurality of disparate touch location detection techniques comprises:

providing a first touch location detection technique that determines x and y coordinates of a touch location relative to the touch sensitive surface; and

providing a second touch location detection technique that determines a z coordinate relative to the touch sensitive surface.

6. The method of claim 1, wherein providing the plurality of disparate touch location detection techniques comprises providing at least one touch location detection technique that provides dispersion correction to the signals generated by at least one bending mode sensor of the plurality of bending mode sensors.

7. The method of claim 1, wherein developing the touch location information comprises determining displacement of the touch sensitive surface using at least one of the plurality of touch location detection techniques.

8. The method of claim 7, wherein developing the touch location information comprises determining a time of flight of bending waves generated by a touch on the touch sensitive surface using at least one of the plurality of touch location detection techniques.

9. The method of claim 7, wherein developing the touch location information comprises correcting for dispersion of the signals generated by at least one bending mode sensor of the plurality of bending mode sensors.

10. The method of claim 1, wherein developing the touch location information comprises:

confirming a touch on the touch sensitive surface using one of the plurality of touch detection techniques; and

determining a location of the touch on the touch sensitive surface using another of the plurality of touch detection techniques.

11. A touch sensitive device, comprising:

a plurality of touch sensors configured to detect bending of a touch sensitive surface resulting from a touch to the touch sensitive surface; and

processing circuitry configured to implement a plurality of disparate touch location detection techniques, the touch location detection techniques including a first and second touch location detection technique at least one of which uses signals generated by the plurality of touch sensors, the processing circuit also being configured to develop touch location information about the touch using the disparate touch location detection techniques in such a way that a coarse location for the touch is determined using the first touch location technique, and the determined coarse location is used to enhance a touch location determination made by the second touch location technique to provide a fine location for the touch, the fine location being more accurate than the first and second touch location techniques alone.

12. The device of claim 11, wherein at least one of the plurality of touch sensors is sensitive to a first frequency range and at least one other of the plurality of touch sensors is sensitive to a second frequency range that differs from the first frequency range.

13. The device of claim 11, wherein at least one of the plurality of disparate touch location detection techniques is sensitive to a first frequency range and at least one other of the plurality of disparate touch location detection techniques is sensitive to a second frequency range that differs from the first frequency range.

14. The device of claim 11, wherein the plurality of touch sensors are sensitive to the same frequency range.

15. The device of claim 11, wherein at least some of the plurality of disparate touch location detection techniques are capable of independently detecting a touch location.

16. The device of claim 11, wherein the touch location information comprises a z coordinate of the touch relative to the touch sensitive surface.

17. The device of claim 11, wherein the touch location information comprises a force of the touch on the touch sensitive surface.

18. The device of claim 11, wherein at least some of the plurality of disparate touch location detection techniques use bending waves sensed by some of the plurality of touch sensors to develop the touch location information.

19. The device of claim 11, wherein at least some of the plurality of disparate touch location detection techniques use displacement of the touch sensitive surface sensed by at least one of the plurality of touch sensors to develop the touch location information.

20. The device of claim 11, wherein the processor is configured to confirm a touch on the touch sensitive surface using one of the plurality of touch detection techniques and to determine a location of the touch on the touch sensitive surface using another of the plurality of touch detection techniques.